The Inhibition of PMSG-induced Ovulation in Immature Rats by Melatonin

Summary The subcutaneous or oral administration of melatonin to immature rats which had received PMSG to induce follicular growth and ovulation caused a significant reduction in the incidence of ovulation. Furthermore, the administration of HCG concurrently with melatonin overrode the inhibitory effect of melatonin. These observations support the concept that the pineal gland exerts control over reproductive functions via an inhibitory action of melatonin on the release of hypophyseal gonadotropins.